1. Field of the Invention
The invention relates to a crankcase breathing system for an internal combustion engine, comprising at least one oil separating apparatus with a preliminary separator and a main separator arranged downstream of the same, with the preliminary separator comprising a diffuser between an inlet and an outlet which expands in the direction of flow. The invention further relates to a liquid-cooled internal combustion engine with a crankcase for several cylinders with a cooling jacket about the cylinders in the crankcase, with individual cylinder heads with at least two cooling chambers arranged above one another in the cylinder head, with the cooling jacket of the crankcase and the bottom cooling chamber in the cylinder head being connected with each other via at least one, preferably at least four, transfer openings which are evenly distributed on the circumference of the cylinder. The invention also relates to a multi-part pulley, especially a poly-V pulley. The invention further also relates to an internal combustion engine with an oil pump whose feed pressure can be limited by a control valve, with the control valve having a spring-loaded control piston which is displaceable in the control cylinder, and with a gradual-removal chamber formed by control piston and control cylinder being connected with an oil return line.
2. The Prior Art
An oil preliminary separator is known from AT 006.652 U1 which can be provided upstream of a main oil separator in a crankcase breathing system. The preliminary separator comprises a diffuser between inlet and outlet which expands in the direction of flow. High separation rates can thus be achieved.
DE 31 07 191 A1 describes a crankcase breathing system for an internal combustion engine, comprising a funnel-like liquid separator which comprises a separator packing and an upwardly facing screen. An annular collecting chamber for separated liquid is arranged in the area of the transition to a downwardly arranged breathing line. The lowest point of the annular collecting chamber is the starting point for a liquid discharge line which is arranged in the interior of the breathing line, reaches back up to the crankcase and is guided here into a steadied-flow zone.
FR 2 332 424 A discloses an oil separator for an internal combustion engine which comprises a double cone between the inlet and outlet, which double cone expands in a first section in a diffuser-like way. This is then followed by a funnel-like section in which the cross section tapers until the discharge from the oil separator. A number of baffle plates is arranged in the oil separator which improve the separation of the oil. The entrainment of especially small oil drops still cannot be prevented in the case of especially high flow quantities.
A cylinder head for several cylinders for a liquid-cooled internal combustion engine is known from AT 005.301 U1, comprising a cooling chamber arrangement adjacent to a fire deck which is subdivided into a fire-deck-side bottom partial cooling chamber and an upper partial cooling chamber adjacent thereto in the direction of the cylinder axis by an intermediate deck extending substantially parallel to the fire deck. The bottom and upper partial cooling chamber are flow-connected with each other via an annular overflow opening about an injection device. The coolant reaches the bottom partial cooling chamber through at least one inlet bore per cylinder arranged in the fire deck, flows through the same in the transversal direction and reaches the upper partial cooling chamber through the annular overflow opening.
DE 103 12 190 A1 discloses a crankcase with wet liners which are enclosed by cooling chambers. The cooling chambers are in connection with a distributor duct arranged in the area of a longitudinal side wall of the crankcase, above which a collecting duct is arranged.
Poly-V belts are especially suitable for transmitting drive and tension forces at high belt speeds and minute disk diameters and have especially favorable running and transmission properties. Highly flexible poly-V belts are described in DD 270 117 A1 for example.
Furthermore, a drive device for an auxiliary machine unit with a driven poly-V pulley is known from DE 102 00 686 A1.
As a result of the small dimensioned poly-V belt application surfaces, poly-V belts are more sensitive to dirt, rust and porous frictional surfaces in the grooves than known narrow V-belts. Poly-V pulleys therefore must offer high surface quality in the area of the belt application surfaces. Especially in the case of poly-V belt disks arranged in several steps, a considerable production effort is required for achieving high surface quality.
Multi-part pulleys for simple belts are known from EP 0 100 756 A1 or U.S. Pat. No. 4,193,310 A. The pulley consists of two mutually connected disk holding parts, with the receiving surfaces for the belts being formed by both disk holding parts.
EP 0 875 678 A2 discloses an oil pump with a control valve, with the control valve comprising a control piston displaceable in a cylinder. The control pressure is formed by the pump pressure applied directly onto the pressure side of the pump. The oil is supplied to a main intake opening or an ancillary intake opening of the pump depending on the pump pressure.
In the case of oil pumps with gradual removal into the suction chamber, the desired oil pressure in the main oil duct is achieved in that the spring of the control valve in the oil pump is set higher by the flow resistances of the downstream oil cooler and oil filter. The disadvantageous aspect is that especially in the case of cold starting the oil pressure build-up is delayed.
It is the object of the invention to avoid these disadvantages and to achieve optimal oil separation with the lowest possible effort in all operating ranges of the internal combustion engine. It is a further object to achieve an optimal and even cooling of thermally critical areas. It is also an object of the invention to provide a pulley that can be produced in a cost-effective way. It is further an object of the invention to enable rapid oil pressure build-up especially during cold starting.